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calcined white, the Orthoclase was nearly white, and was broken 
up into thin plates with loss of cohesion, following the direction 
of its cleavage-planes, the core of the felspar showed the 
markings as in Cohen’s work (T. xx.f. 4). The mica had 
changed from dark bottle green to a very pale yellow, and some 
parts had even lost their colour entirely. The whole of the 
indications point to a state of calcination, but to a degree of 
temperature yet by no means approaching fusion point. The 
disintegration was complete, and had it been, whilst hot, thrown 
into cold water, would have gone to powder. 
Experiment 8. Next, some quartz grains and crystals 
were extracted from the granite, measuring about 5 mm. across, 
and were raised by blast toa heat of a light Orange colour, 
and then cooled quickly by covering them with cold water. 
The quartz was reduced to a friable state, cracks generally ran 
along the cleavage-planes and it could be crushed easily 
between the fingers. The colour markings had faded altogether. 
An illustration of the bleaching of the red Orthoclases may 
be seen in the case of the orthoclase granite—from which the 
charming porcelain ware is manufactured at Belleck, near 
Lough Erne, County Fermanagh, in Ireland. The works are 
built close to the quarries from which the material, a granitoid 
stone, containing a high percentage of orthoclase felspar is got 
out. Professor Hull says that the red felspar retains its 
crystalline form in its original perfection, and on being cal- 
cined loses its original colour and becomes white. The metallic 
_ iron which separates in specks from the rock during the process 
of calcination, is afterwards extracted by simply immersing 
magnets into the powdered china clay when mixed with water, 
the particles of iron then adhere and are lifted out. 
At Worcester China Works a different course slightly 
varying from this is practised, at least for making the finest 
porcelain, the powdered china clay (kaolin) is combed with 
magnetic combs whilst dry, the object being to catch, detain, 
and remove the iron that is found in almost all granites, as 
pyrite and magnetites; a small speck of iron pyrite would, 
after the china came from the kiln, sol ri on it as a blemish 
in the form of a yellow spot. 
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